Well packer and testing apparatus

ABSTRACT

Apparatus for testing a well packer having a supporting body anchored to a surrounding well conduit and on which is carried a seal member for forming a fluidtight seal between the surrounding well conduit and the supporting packer body. The testing apparatus may comprise an inner well conduit concentrically disposed within the surrounding well conduit and to which is attached a tubular mandrel for disposition within the supporting packer body to form an annular flow passage in fluid communication with the annulus between the two well conduits. Annular pack-off means comprising a cylindrical sleeve member is carried by the mandrel for axial movement from a first position above the annular passage to a second position sealingly engaging this flow passage and preventing flow of fluids from the annular passage through the annulus between the well conduits. The sleeve member may be mounted on the mandrel for limited axial movement relative thereto and may be initially prevented from axial movement relative to the mandrel by hold-down means. The holddown means may be adapted to release the sleeve member in response to pressure applied to one end thereof so as to permit its limited axial movement relative to the mandrel. The hold-down means also includes cooperable friction means on the mandrel and the sleeve member responsive to pressure applied to the opposite end of the sleeve member to permit axial movement in one direction while restricting movement in the opposite direction.

United States Patent [191 Brown et al.

[111 3,826,307 [451 July 30, 1974 WELL PACKER AND TESTING APPARATUS [75]Inventors: Cicero C. Brown; Chudleigh B.

Cochran, both of Houston, Tex.

[73] Assignee: Brown Oil Tools, Inc., Houston,

Tex.

[22] Filed: Sept. 25, 1972 [21] Appl. No.: 292,136

Primary Examiner-James R. Boler Assistant ExaminerPeter Nerbum Attorney,Agent, or Firm-Torres & Berryhill [57] ABSTRACT Apparatus for testing awell packer having a supporting body anchored to a surrounding wellconduit and on which is carried a seal member for forming a fluidtightseal between the surrounding well conduit and the supporting packerbody. The testing apparatus may comprise an inner well conduitconcentrically disposed within the surrounding well conduit and to whichis attached a tubular mandrel for disposition within the supportingpacker body to form an annular flow passage in fluid communication withthe annulus between the two well conduits. Annular pack-off meanscomprising a cylindrical sleeve member is carried by the mandrel foraxial movement from a first position above the annular passage to asecond position sealingly engaging this flow passage and preventing flowof fluids from the annular passage through the annulus between the wellconduits. The sleeve member may be mounted on the mandrel for limitedaxial movement relative thereto and may be initially prevented fromaxial movement relative to the mandrel by hold-down means. The hold-downmeans may be adapted to release the sleeve member in response topressure applied to one end thereof so as to permit its limited axialmovement relative to the mandrel. The hold-down means also includescooperable friction means on the mandrel and the sleeve memberresponsive to pressure applied to the opposite end of the sleeve memberto permit axial movement in one direction while restricting movement inthe opposite direction.

20 Claims, 10 Drawing Figures PATENTED M3 01974 SHEET 10$ 3.

WELL PACKER AND TESTING APPARATUS BACKGROUND OF THE INVENTION 1. Fieldof the Invention The present invention pertains to well packers andapparatus for testing the sealing of well packers with a surroundingwell conduit. The invention is particularly directed to an improvementfor assuring a proper seal between the sealing element of a gravelpacker and the surrounding well conduit.

2. Description of the Prior Art Gravel packing is a procedure employedto form a filter body in the annulus between the wall of a relativelyunconsolidated oil producing formation in a well bore and the productionpipe. Normally the latter includes a section of pipe, commonly termed aliner, having a plurality of narrow spaced apart apertures or havingscreen covered openings through which the formation fluids enter theproduction pipe from the formation while the gravel body interposedbetween the liner and the formation walls serves to support theunconsolidated formation and, at the same time, aiding in screening outtine sand and the like from the fluids, so that clean fluids may enterthe production pipe.

Until a few years ago gravel packing tools have comprised separate linersetting tools and gravel placing devices which are relativelycomplicated in form and subject to various types of difficulties insetting in place in the well bore and in conducting the gravel packingoperation. In recent years simplified assemblies have been developedwhich include a liner hanger and packer, as well as a gravel packingtool, all combined into compact easily operated and efficient gravelpacking assemblies. Some of these assemblies are provided with across-over arrangement in the gravel packing tool by which fluid may beselectively circulated through the tubing or inner pipe string to theannulus below an intervening packer seal or in the reverse dircctionfrom the annulus to the tubing string. Some of these assemblies alsoprovide a hydraulic pressure actuated liner hanger in combination with apacking seal for the well bore in which the cross-over arrangement maybe used to selectively deliver actuating pressure fluid to the linerhanger and washing fluid to the production formation, as well as gravelcarrying fluid for packing the annulus between the formation and theliner.

Such a tool and packer assembly is disclosed in U.S. Pat. No. 3,072,204issued to Cicero C. Brown on Jan. 8, I963. The gravel packing assemblydescribed in that patent is provided with ports between the inner andouter strings and sleeve valve arrangements which are operable forcontrolling the ports during the conducting of the several stages insetting and releasing of the gravel packing tools and in conducting thegravel packing operation. Although such an assembly offers manyadvantages over separate liner setting tools and gravel SUMMARY OF THEPRESENT INVENTION The present invention is directed to an improvement ina combination well packer and tool assembly such as is described in theaforementioned U.S. Pat. Nof

3,072,204 specifically designed for more easily and efficientlyconducted gravel packing operations. In particular the improvement isdirected toward providing a means by which the seal between the packerand surrounding well conduit may be tested to assure a fluidtight seal.Another object of the invention is to provide a means by whichadditional forces may be applied to the packer seals to assure sealingunder all conditions. Although the testing apparatus of the presentinvention was primarily designed for use with such a gravel packarrangement, it is not so limited. It may be used with other wellpackers to test the sealing engagement of such a packer with thesurrounding well conduit.

In summary, the apparatus of the invention comprises a tubular mandrelwhich may be attached to an inner well conduit or tubing string fordisposition within a surrounding supporting body forming a portion ofthe well packer. An annular flow passage is formed between thesupporting body and tubular mandrel to provide fluid communication froma point below the packer seal and the annulus between the outer andinner well conduits. An annular pack-off means is carried on the tubularmandrel and is axially movable from a first position above the annularflow passage to a second position sealingly engaging the flow passagepreventing flow of fluids between the annulus surrounding the inner wellconduit and the bore of the well beneath the packer seal. Thus theannulus between the inner and outer well conduits may be pressurized tocheck the packer seal. If there is a leak it will be detected by anincrease in pressure or fluid flow through the inner well conduit.

The annular pack-off means may comprise a cylindrical sleeve memberwhich is mounted on the tubular mandrel for limited axial movementrelative thereto and which is provided with an annular seal for engagingthe supporting packer body within the annular passage bounded thereby.The sleeve member may be affixed to the mandrel by hold-down means whichincludes a retainer device responsive to pressure applied to one end ofthe sleeve member to affect its release to permit limited axial movementrelative to the mandrel. With such an arrangement additional forces maybe applied to the packer seal for assuring fluidtight engagement withthe surrounding well conduit.

The pack-off means may be displaced from the annular passage by applyingpressure to the lower end thereof through the inner well conduit,allowing further operations to be conducted. The hold-down means maycomprise cooperable friction apparatus on the mandrel and sleeve memberpermitting the sleeve member to be displaced from the annular passageand preventing its reengagement therewith.

Thus the invention provides an improved well packer and tool assemblywhich allows the packer seal to be tested prior to conducting furtheroperations. This is extremely important in gravel packing since it issometimes difficult and expensive to remove a nonfunctioning packerafter gravel placement. In addition to providing a means for testing thepacker seal, the present invention provides a means by which the packermay be more firmly anchored within the well conduit and by which thepacker seal may be assured of greater sealing forces. Other objects andadvantages of the invention will be apparent from a reading of thefollowing description in conjunction with the accompanying drawingswhich illustrate a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is alongitudinal quarter sectional view showing a tool and packer assembly,according to a preferred embodiment of the invention, in the runningposition within a surrounding well conduit;

FIG. 2 is a longitudinal sectional view of the tool and well packerassembly of FIG. 1 shown in the set position;

FIG. 3 is a longitudinal quarter sectional view showing the upperportion of the tool and packer assembly of FIGS. 1 and 2 in the runningposition;

FIG. 4 is a longitudinal sectional view of the portion of the tool andwell packer assembly shown in FIG. 3 in the first stage of setting thepacker seal;

FIG. 5 is a longitudinal sectional view, similar to FIG. 4, showing thetool in a subsequent downwardly displaced position in which a portion ofthe tool has engaged a portion of the packer for actuating the seal andin which the pack-off means carried thereby has engaged the annularpassage between the mandrel and the surrounding well packer supportingbody;

FIG. 6 is a longitudinal sectional view, similar to FIGS. 4 and 5,showing the subsequent step in which pressure has been applied to theupper end of the packoff means to release it for limited axial movementon the mandrel and to further compress the pack-off seal;

FIG. 7 is a longitudinal sectional view, similar to FIGS. 4-6, showing asubsequent stage in which the pack-off means has been displaced fromengagement with the annular passage permitting graveling operations toproceed;

FIG. 8, taken along line 8-8 of FIG. 3, is a cross sectional view of aportion of the setting tool, according to a preferred embodiment of theinvention;

FIG. 9, taken along line 99 of FIG. 5, is a cross sectional view of thesetting tool illustrating the pack-off means prior to its release forlimited axial movement on the mandrel; and

FIG. 10, taken along line 10-10 of FIG. 6, is a cross sectional view ofthe setting tool after release from the mandrel and slight axialdisplacement thereon.

DESCRIPTION OF A PREFERRED EMBODIMENT ployed in gravel packingoperations having slots or perforations (not shown) in its walls throughwhich fluid may pass, but preventing the passage of particulatematerials above a predetermined size. The lower end of the liner 13 maybe closed by a plug (not shown). The liner is normally positioned sothat it is surrounded by the zone or formation from which the well willproduce. After graveling operations the petroleum deposits from theformation will first filter through the gravel pack then pass throughthe liner 13 into the production string to the surface of the well.

The upper end of the liner hanger body 11 is internally threaded toreceive the lower end of the tubular supporting body 14 of a wellpacker. Carried on the supporting body 14 is an annular packer seal 15disposed between a pair of setting cones or expanders 16 and 17. Bothconical expanders 16 and 17 are slidable on the exterior of packer body14. However, seal 15 and conical expanders 16 and. 17 are prevented frompremature displacement by a lower snap ring 18 and shear pin 19 (seeFIG. 3). Threadedly attached to the upper end of packer body 14 is anannular ring 20 from which depends a plurality of resilient arms 21 atthe ends of which are toothed slips 22. The slips 22 are adapted toslide over conical expanders 17 in response to relative motions betweenpacker body 14 and cone 17. Another set of resilient arms 23 and slips24 are attached to a cylinder 25 and the slips 24 are adapted to slideover the conical surface of cone 16 in response to movement of cylinder25 relative to packer body 14.

The cylinder 25 surrounds the upper end of liner hanger body 11 in atelescopic sliding fit and is initially seated in its lowermost positionon an annular shoulder 26 of liner hanger body 11. A shear pin 27 servesto temporarily secure the cylinder 25 to liner hanger body 11 in thislowermost position. A seal ring 28 is mounted in an appropriate grooveon hanger body 11 to form a slidable fiuidtight seal between the hangerbody 11 and cylinder 25. The bore of cylinder 25 is reduced at its upperend to form a cylinder head 29 which is disposed in a close sliding fitabout the exterior of packer body 14. An annular seal 30 creates aslidable fluidtight seal between the cylinder head 29 and packer body14. A variable volume annular chamber 31 is provided between cylinderhead 29 and the upper end of the liner hanger body 11 and is incommunication with an annular space 32 provided by clearance between theexterior of the upper end of the hanger body I l and the interior ofcylinder 25. Annular space 32 and the variable chamber 31 communicatewith one or more ports 33 extending radially through the wall of hangerbody 11 at a point above seal ring 28. Ports 33 communicate with apressure fluid supply, as will be described hereafter.

concentrically disposed within the packer body 14, leaving an annularspace 34 therebetween, is a tubular mandrel 35 which makes up a part ofthe running tool of the assembly A. The upper end of mandrel 35 isthreadedly received within a coupling K by which the entire assembly Ais connected to the tubing string T. A shoulder ring 36 rotatinglysurrounds the upper end of mandrel 35 and is maintained thereon by asnap ring 37. A roller bearing 38 also surrounds the upper end ofmandrel 35 and is disposed between the lower end of coupling K andshoulder ring 36. A cylindrical sleeve or collar 39 is attached toshoulder ring 36 and, as will be more fully understood hereafter, isadapted to rest on the upper end of annular ring 20 to transmit theweight of the tubing string T to the packer body 14 when the mandrel 3Sand tubing string '1 are lowered sufficiently. Because of the rotationalmounting of ring 36 and bearing 38 mandrel 35 may be rotated when sleeve39 engages ring 20 without disturbing the position of sleeve 39. Alsomounted on mandrel 35 is a pack-off assembly 40, the details andfunction of which will be more fully described hereafter.

Near its lower end the mandrel 35 may be provided with a cross-over headwhich may comprise cylinder 41 connected to mandrel 35 by segments orlugs 42 through which passages 43 are provided, including ports 44 inmandrel 35 and ports 45 in cylinder 41, providing fluid communicationbetween the interior of mandrel 35 and the exterior of cylinder 41. Ascan be seen from the drawings, mandrel 35 terminates at a point above aconnector coupling 46 so that an annular opening 48 communicates withthe passageway 49 formed between cross-over head cylinder 41 and thelower end of mandrel 35.

' The lower end of cross-over head cylinder 41 is threadedly attached tothe reducer coupling 46 to which is threadedly connected a flow tube 47.Although it is not shown, the flow tube 47 is open at its lower end andextends through the bore of liner 13 to a point adjacent to thelowermost slots or perforations (not shown) of liner 13.

A tubular releasing sleeve 50 is concentrically interposed between thecross-over head and the inner wall of hanger body 11. This sleeve 50 isnormally slidable axially within hanger body 11, but is temporarily heldagainst movement in its uppermost position by means of a shear screw 51which extends through the wall of hanger body 11 into the sleeve 50. Atits lower end the exterior of releasing sleeve 50 is reduced in diameterto provide an annular shoulder 52 adapted to receive the upper end of acoiled compression spring 53. The lower end of spring 53 similarlysurrounds a reduced diameter portion of coupling 12 exerting a forceagainst an annular shoulder 12a. The spring 53 serves to bias thereleasing sleeve 50 toward its uppermost position after shear screw 51has been broken, as will be subsequently described. The upper end ofreleasing sleeve 50 is adapted to abut the lower end of packer body 14when the releasing sleeve is in its uppermost position, as illustratedin FIG. 1. A longitudinal groove 54 is formed in the outer wall of thereleasing sleeve 50, extending from a point above shear screw 51 for ashort distance, and is adapted to receive an indexing screw 55 whichprojects inwardly from the wall of hanger body 11 to prevent relativerotation between releasing sleeve 50 and hanger body 11, yet permittinglimited relative axial movement therebetween after shear screw 51 hasbeen released. An annular seal ring 56 is disposed between the exteriorof releasing sleeve 50, just above shoulder 52, and the interior ofhanger body 11 to form a fluidtight slidable seal between the lowerportion of releasing sleeve 50 and hanger body 11. Similar seal rings 57and 58 are provided between releasing sleeve 50 and hanger body 11 onopposite sides of an annular space 59 formed by the reduction of theexterior of releasing sleeve 50, to form fluidtight slidable seals withthe bore of hanger body 11. The releasing sleeve 50 is also providedwith ports 60 which may provide a continuation of passage 43 in thecross-over head 41.

A section of coarse threads 61 may be provided on the upper interior ofreleasing sleeve 50 for connection with complimentary threads formed onthe exterior of cross-over head 41 near its upper end. These threads areprovided to permit release of the cross-over head 41, mandrel 35 andflow tube 47 from the assembly A at a suitable stage in the operations,as will be subsequently described. Seal rings 62 and 63 are providedbetween the cross-over head and releasing sleeve 50.

Passages 43, including ports 44, 45 and 60, provide fluid communicationbetween the interior of mandrel 35 and the annular space or channel 59surrounding the upper end of releasing sleeve 50. Axial passage 49,including annular port 48, provides fluid communication between theinterior of mandrel 35, the annular space 34, surrounding the mandrelwithin packer body 14, and the annular space B between casing C andtubing string T.

A sleeve valve 64 is mounted in the bore of mandrel 35 for controllingflow through these passages 43 and 49. The sleeve valve 64 includes atubular body 65 which is slidably disposed in the bore of mandrel 35 andis provided at its upper end with a frusto-conical seat 66 for receptionof a suitable closure member, such as plug P, as in FIG. 2. At a pointintermediate its ends, the sleeve body 65 is provided with a pluralityof radial ports 67 which are adapted to be moved into and out ofregistration with annular port 48. The portion of the valve body 65above port 67 serves to open and close ports 44, or the inner ends offluid passages 43, depending upon the position of the valve body, aswill be subsequently described.

As shown in FIG. I, the sleeve body 65 is in its uppermost position inwhich both passageways 43 and 49 are closed. Seal rings 68, 69 and 70are disposed between the sleeve body 65 and the bore of mandrel 35 toprovide sliding seals for isolating the passages 43 and 49 in both openand closed positions. A snap ring 71 is suitably mounted on the exteriorof sleeve valve body 65 at a point below seal ring 70 and is adapted toengage a tapered surface 72 at the upper end of reducing coupling 46 toreleaseably lock the sleeve valve 64 in the uppermost position ofFIG. 1. It will be understood that by exertion of sufficient downwardpressure on the upper end of valve body 65, snap ring 71 can becompressed sufficiently to force it inwardly and allow the sleeve valvebody 65 to be moved downwardly. A snap ring groove 73 is provided withinreducer coupling 46 and is adapted to receive the snap ring 71 when thesleeve valve has traveled downwardly a sufficient distance to place thesnap ring 71 opposite groove 73, as in FIG. 2. In this position thesleeve valve will be locked so as to place ports 67 in registration withannular port 48 and the upper end of the sleeve valve will have moved toa point below port 44 thereby opening the latter for communication withflow passage 43 of the cross-over head.

Referring now also to FIG. 3 a more detailed description of the packoffassembly 40 and the upper portion of mandrel 35 will be given. Thepack-off assembly 40 may comprise a composite body which surrounds theupper portion of mandrel 35 in an axially sliding fit. The body 80 maybe conveniently formed of upper and lower tubular sections threadedlyconnected at 81 to facilitate the assembly of an annular pack-off seal82. A seal ring 83 may be disposed between the interior of body 80 andthe exterior of mandrel 35 to provide a fluidtight sliding sealtherebetween. The pack-off assembly 40 may initially be maintained inthe position shown in FIG. 3 by hold-down means which includes anannular retainer ring 84 engaging a corresponding annular groove 85 onthe mandrel 35. The bore of the lower body section may be counterboredto provide a shoulder 86 against which one end of the ring 84 rests. At-I tached to the upper body section by a shear screw 87 is a ring 88which abutsthe opposite end of retainer ring 84 preventing the pack-offassembly 40 from being displaced axially downward until a sufficientforce is applied to break the shear screw 87. It can be understood thatif a sufficient force is applied to the upper end of body 80 shear screw87 will be broken allowing the body 80 to move downwardly relative toring 88 and retainer ring 84 until snap ring 84, which is radiallycompressed, is allowed to expand into the space vacated by ring 88 (seeFIG. 6). The hold-down means also comprises friction means which mayinclude an expandable ring 89 having downwardly directed teeth on itsinterior which correspond with upwardly directed teeth 90 on theexterior of mandrel 35. The purpose of the friction means is to allowmovement of the pack-off assembly 40 in an upward direction, relative tomandrel 35, 'while restricting the downward movement thereon, as will bemore fully understood hereafter. The packoff assembly is also providedwith an inwardly directed annular shoulder or flange 91 and flow ports92 the function of which will be understood hereafter.

The body 80 of the pack-off assembly may reciprocate, unless preventedfrom doing so by the hold-down means within the annular space 93 boundedon the interior by mandrel 35 and on the exterior by sleeve 39. Thesleeve 39 also includes ports 94 which provide communication between theupper end of annular area 93 and the annulus B between casing C andtubing string T. The sleeve 39 also includes another set of ports 95which may provide flow communication between the annular passage 34within packer body 14 and the annulus B above the sleeve 39. The outsidediameter of sleeve 39 is less than the inside diameter of casing Callowing free passage of fluids on the exterior of sleeve 39.

The pack-off assembly 40 and the sleeve 39 make up a considerable partof the improvements in the present invention over the prior art. Exceptfor these components, a change in the well packer construction and minordifferences in the remaining portion of the assembly A, it is similar tothe liner, well packer and tool assembly described in the aforementionedU.S. Pat. No. 3,072,204 and operates in much the same fashion, but withthe highly significant ability to test the well packer seal and to applyadditional sealing forces thereto.

In operation the assembly A is run through the casing C attached to thelower end of tubing string T as shown in FIG. 1. The assembly is loweredwithin casing C to a pointwhere the liner 13 is substantially surroundedby the producing formation (not shown). When the assembly has obtainedthis position, circulation of washing fluid may be initiated by pumpingfluid down through the bore of tubing T, mandrel 35 and flow tube 47,the fluid flowing out the open end of flow tube 47, out the perforations(not shown) in liner 13 and thence upwardly to the surface of the wellthrough the annulus B. Of course, circulation can be conducted while theassembly A is being lowered into the well. The washing fluid, circulatedas described, may be employed to clean the liner l3 and to wash out theface of the formation to provide more capacity for the reception ofgravel when the latter is introduced. It will also be seen that when theparts of the assembly are in the initial running in position, sleevevalve 64 will be positioned to close the entrance of passages 43 and 49through the cross-over head. Therefore, no fluid can pass from theinterior of the cross-over head to the exterior thereof, except as itmay flow down through the flow tube 47 and up past the assembly Athrough the annulus B.

When the assembly A has been lowered to the desired position in the wellbore, a closure member, such as plug P, may be dropped through thetubing string and pumped down with fluid until it rests on the seat 66at the upper end of sleeve valve 64, thereby closing off the portion ofthe bore of the string below the upper end of sleeve valve 64. Aspressure is applied to the plug P, the snap ring 71 is compressed andthe plug P is forced downwardly with sleeve valve 64 until the snap ring71 engages the groove 73. At this point the entrance of passage 43through ports 44 will be opened and ports 67 will be in registrationwith annular port 48 for entrance into passage 49.

The opening of passage 43 will then permit the pressure fluid to flowthrough port 60 in releasing sleeve 50, through the clearance 59surrounding the upper end of releasing sleeve and port 33 in hanger body11, into the annular space 32 and variable annular chamber 31 beneaththe cylinder head 29. When this pressure has obtained a magnitude greatenough to shear screws 27 they will break, allowing cylinder 25 to moveupwardly.

This causes slips 24 to move upwardly and outwardly over the taperedsurface of conical expander 16, wedging the slips 24 into grippingengagement with the wall of easing C and anchoring the packer body 14and the liner string therebelow to the casing. Since, at this stage ofoperation, there is no other outlet from the interior of the tubingstrings, except to cylinder 25, the fluid pressure thus exerted will actvery quickly to anchor the slips. This position is best shown in theFIG. 4.

When the slips 24 have been anchored, the tubing string T is loweredsufficiently to bring sleeve 39 into contact with the upper slip ring 20(FIG. 2 and 5) and sufficient weight is applied through the tubingstring T to move the packer body 14 downwardly relative to the lowerslips 24. Since the slips 24 are wedged between the casing C andexpanding cone 16, they will remain stationary causing the packer seal15 to be compressed between lower expander 16 and upper expander 17.When a sufficient force is applied the shear screw 19 will breakallowing the expander 17 to move upward relative to hanger body 14wedging the upper set of slips 22 into anchoring engagement with thecasing C. See FIG. 5. Continued force causes the packing seal 15 to beexpanded radially to form a fluidtight seal between the packer body 14and the wall of easing C. The lower slips 24 maintain the seal on thelower side while the upper slips 22 maintain the seal from above andprevent upward movement of the well packer. At this stage of operationsthe pack-off assembly 40 will have sealingly engaged the annular passage34 between mandrel 35 and packer body 14, blocking flow from passage 34into the annulus B.

Lowering of the tubing T in the manner just described will applysufficient downward pressure on the cross-over head 41 and releasingsleeve 50 to break shear screws 51, allowing these components to movedownwardly relative to the hanger body 11, spring 53 being compressed bythis movement. See FIG. 2. This downward movement of the cross-over headand releasing sleeve 50 will bring passages 43 and port intoregistration with discharge ports 11a in the hanger body 11. Were it notfor pack-off assembly 40'fluid circulation could then be developedbetween tubing string T and annulus B by circulation through passage 43,ports 60 and 11a through the liner l3 and flow tube 47, through axialpassage 49 in the cross-over head and annular passage 34. In fact, withthe prior art apparatus, graveling operations would proceed bycirculating particulate laden fluid in this manner without first testingthe packer seal 15.

With the improvement of the present invention, the packer seal 15 may betested at this stage of operations to assure that an effective seal hasbeen obtained before graveling takes place. If the seal is fluidtightgraveling may proceed, but if it is not remedial steps can be takenwithout the complications which necessarily arise after gravel has beendeposited around the liner 13.

With the assembly A in the positions of FIG. 2 and 5 testing may proceedby applying test pressure to the annulus B. The pressure fluid isapplied through ports 94 and 95 to the upper end of the pack offassembly 40. When a sufficient pressure differential exists, shear screw87 will be broken allowing the pack-off body 80 to move downwardlyrelative to mandrel 35 until retainer ring 84 expands into the spacevacated by ring 88 as shown in FIG. 6. At about this point the taperedshoulder 80a of the pack-off assembly will contact slip ring causingadditional downwardly directed forces to be applied to packer body 14and upper slips 22, further setting the seal 15 if so desired. Then testpressure may be maintained for a sufficient time to determine that aleak does not exist in the well packer seal. If a leak does exist thepressure will drop and there will be a corresponding increase in thepressure or fluids in the tubing string T.

Once it has been determined that the packer seal 15 is properly set thepack-off assembly 40 must be displaced axially upward relative tomandrel 35 to allow graveling operations to proceed. This isaccomplished by relieving the pressure in annulus B and applying apressure to the lower end of pack-off assembly 40 through tubing stringT passage 43, ports 60 and 11a, liner 13, flow tube 47 and passage 49.When this pressure is sufficiently high, the pack-off assembly 40 willbe forced upwardly to the position shown in FIG. 7. As the pack-offassembly 40 moves upward the ring 88 contacts the bottom of frictionring 89 causing it to expand and contract as its downwardly directedteeth ride over the upwardly directed teeth 90 of mandrel 35. Once thepack-off assembly has been moved to the upper position it is restrictedfrom downward movement by the engagement of body shoulder 91 with theupper end of friction ring 89. Since the teeth on the friction ring 89are directed downwardly and the teeth 91 on mandrel 35 are directlyupwardly the ring 89 will not expand and consequently will prevent thereengagement of the pack-off assembly 40 with the annular passage 34.

Once the pack-off assembly 40 is displaced to the position shown in FIG.'7, fluid circulation may be reestablished between the annulus B andtubing string T through the mandrel cross-over head passages and theinner connecting ports and passageways. Circulation of fluid in thismanner may be employed to additionally wash out or cavitate the face ofhe producing formation, providing an enlarged capacity for gravel inorder to increase the thickness and volume of the supporting body ofgravel.

Then gravel or particulate matter such as coarse sand may be introducedwith the fluid flowing into the annulus between the formation and theliner 13, being deposited there since the particulate matter selectedwould be of a size so as not to pass through the perforations (notshown) of liner 13. However, the fluid accompanying the gravel orparticulate matter would be strained through the gravel and would flowthrough the perforations, through the lower end of flow tube 47,upwardly through passages 49 and 34 into the annulus B where it would bereturned to the surface. If desired the assembly could be back washed bysimply reversing circulation through the annulus B and out tubing stringT.

Once gravel packing has been completed, as described, the mandrel 35along with pack-off assembly 40, the cross-over head and flow tube 47may be withdrawn. This is accomplished by picking up on the tubingstring sufficiently to raise the port of releasing sleeve 50 out ofregistration with discharge ports llla, thereby cutting off thecirculation of fluid to the annulus below the packer seal 15. With thetubing string in its elevated position, the tubing string may be rotateda sufficient number of turns to release the threaded connection 61between the cross-over head 41 and releasing sleeve 50. The tubingstring T, including mandrel 35, pack-off assembly 40, the cross-overheadand flow tube 47, can then be withdrawn from the hanger and packerstructure. When these elements are removed, spring 53 is released fromits previously compressed position to urge the releasing sleeve 50 toits uppermost position, as in FIG. 1, thereby maintaining ports 60 outof registration with discharge ports 11a and preventing passage of fluidfrom the producing formation into the remaining structure, unless thefluid first passesthrough the perforations of line 13.

Once the tubing string 10 and its connecting components have beenwithdrawn, a production tubing string may be installed. This operationis entirely conventional and forms no part of the present invention.

Thus it can be seen that the present invention provides an improvedliner, well packer and tool assembly for graveling operations whichpermit testing of the packer seal prior to graveling. In addition itprovides a means by which the seal may be more firmly set. Furthermorethe anchoring means assures a firm set without having to depend upon theweight of the liner as with packer seals of the prior art.

Although the pack-off assembly 40 and the related sleeve 39 have beendescribed primarily for use with graveling operations, they are not solimited. The invention could very easily be adapted to test other typesof well packers and to apply additional forces for setting such packers.In fact many variations of the invention will be apparent to thoseskilled in the art. The specification, including the abstract, and thedrawings are not to be taken as limiting the invention in any way. It isintended that the scope of the invention be limited only by the claimswhich follow.

We claim:

1. Apparatus for testing a well packer having a supporting body anchoredto a surrounding well conduit and on which is carried a seal member forforming a fluidtight seal between said conduit and said supporting body,said apparatus comprising:

a. an inner well conduit concentrically disposed within said surroundingwell conduit to form a first annular passage therebetween;

a tubular mandrel connected to said inner conduit for disposition withinsaid supporting body to form a second annular passage in fluidcommunication with said first annular passage and the bore of said wellbeneath said packer seal;

annular pack-off means carried by said mandrel axially movable from afirst position above said second annular passage to a second positionsealingly engaging said second flow passage and preventing flow of fluidbetween said bore of said well beneath said packer seal and said secondannular passage;

holddown means comprises retainer means on said 7 mandrel andsaid'sleeve member responsive to pressure applied to one end of saidsleeve member to effect said sleeve member release.

4. Apparatus as set forth in claim 3 in which said retainer meanscomprises a snap ring carried by one of said mandrel and sleeve memberengaging an annular groove in the other. I 5. Apparatus as set forth inclaim 2 in which said holddown means comprises cooperable friction meanson said mandrel and said sleeve member permitting axial movement of saidsleeve member in one direction while restricting movement in theopposite direction.

6. Apparatus as set forth in claim 5 in which said friction meanscomprises an expandable and contractable annular ring with teeth on oneof said mandrel and sleeve member engageable with corresponding teeth onthe other. I

7. Apparatus as set forth in claim 1 in which said mandrel is axiallymovable relative to said supporting packer body, stop means beingcarried by said. mandrel and engageable with said supporting packer bodyto limit said axial movement in one direction.

8. Apparatus as set forth in claim 7 in which said mandrel is initiallyattached to said well packer, said attachment being releasable to permitdownward axial displacement of said mandrel from said initial positionto a position in which said stop means engages said well packer.

9. Apparatus as set forth in claim 7 in which said pack-off means isresponsive to pressure in said first annular passage for further axialmovement in the same direction relative to said supporting packer bodywhile said mandrel remains stationary.

10. In combination a gravel packer and running tool comprising:

a.- a tubular body having a perforate liner attached thereto;

b. resilient seal means carried by said body;

c. anchor means carried by said body operable to anchor said seal meansto a surrounding well conduit and to acuate said seal means for sealingbetween said body and said surrounding conduit;

d. an inner well conduit concentrically disposed in said surroundingwell conduit;

atubular mandrel attached to said inner well conduit and disposed withinsaid body to provide first and second axially extended flow passages forconducting fluids between upper and lower points above and below saidseal means;

f. cross-over flow passage means extending from said first flow passageand opening externally of said tubular body at a point below said sealmeans to provide fluid communication between said first and second flowpassages through said perforate liner; and

. pack-off means carried by said tubular mandrel for limited axialmovement thereon and movable from a first position permitting fluid flowthrough said second flow passage to a second position sealinglypreventing flow through said second flow passage.

11. The combination of claim 10 in which said second flow passagecomprises an annular space surrounding said tubular mandrel within saidtubular body, said pack-off 'means including a first seal member forengagement with the outer confines of said annular space, a second sealmember being disposed between said packoff means and said tubularmandrel providing a sliding sealing tit therebetween.

12. The combination of claim 11 in which said packoff means comprisesholddown means preventing premature axial displacement of said pack-offmeans relative to said tubular mandrel.

13. The combination of claim 12 in which said packoff meansis axiallydisplaceable with said mandrel to sealingly engage and block said secondflow passage.

14. The combination of claim 13 in which said holddown means comprisesretainer means responsive to pressure applied to one end of said packoffmeans to release said pack-off means for said limited axial movement onsaid tubular mandrel.

15. The combination of claim 14 in which said holddown means comprisesfriction means responsive to pressure applied to one end of saidpack-off means to allow said limited axial movement in one directionwhile restricting movement in the opposite direction.

16. The combination of claim 13 comprising stop means carried by saidmandrel and engageable with a portion of said gravel packer to limitaxial movement of said mandrel in one direction relative to said tubularbody.

17. The combination of claim 16 in which said stop means is engageablewith said anchor means to apply additional sealing forces to saidresilient seal means.

18. The combination of claim 10 in which said second flow passagecomprises an annular space bounded on the outside by said tubular bodyand on the inside by said tubular mandrel, said pack-off meanscomprising a cylindrical sleeve member having a first seal member forsealingly engaging said tubular body, a second seal member beingdisposed between said cylindrical sleeve member and said tubular mandrelto provide a sliding sealing fit therebetween, said cylindrical sleevemember being responsive to pressure applied to one end thereof to effectaxial displacement of said cylindrical sleeve member relative to saidtubular mandrel.

20. The combination of claim 19 in which said holddown means comprisesfriction means responsive to pressure applied to the opposite end ofsaid cylindrical sleeve member to displace said cylindrical sleevemember from said annular space and preventing reengagement thereof.

1. Apparatus for testing a well packer having a supporting body anchoredto a surrounding well conduit and on which is carried a seal member forforming a fluidtight seal between said conduit and said supporting body,said apparatus comprising: a. an inner well conduit concentricallydisposed within said surrounding well conduit to form a first annularpassage therebetween; b. a tubular mandrel connected to said innerconduit for disposition within said supporting body to form a secondannular passage in fluid communication with said first annular passageand the bore of said well beneath said packer seal; c. annular pack-offmeans carried by said mandrel axially movable from a first positionabove said second annular passage to a second position sealinglyengaging said second flow passage and preventing flow of fluid betweensaid bore of said well beneath said packer seal and said second annularpassage; d. said pack-off means comprising a cylindrical sleeve memberon which is carried an annular seal for engaging said supporting bodywhen in said second position, said sleeve member being mounted on saidmandrel for limited axial movement relative to said mandrel. 2.Apparatus as set forth in claim 1 in which said sleeve member is affixedto said mandrel by holddown means, said holddown means being adapted torelease said sleeve member for said limited axial movement.
 3. Apparatusas set forth in claim 2 in which said holddown means comprises retainermeans on said mandrel and said sleeve member responsive to pressureapplied to one end of said sleeve member to effect said sleeve memberrelease.
 4. Apparatus as set forth in claim 3 in which said retainermeans comprises a snap ring carried by one of said mandrel and sleevemember engaging an annular groove in the other.
 5. Apparatus as setforth in claim 2 in which said holddown means comprises cooperablefriction means on said mandrel and said sleeve member permitting axialmovement of said sleeve member in one direction while restrictingmovement in the opposite direction.
 6. Apparatus as set forth in claim 5in which said friction means comprises an expandable and contractableannular ring with teeth on one of said mandrel and sleeve memberengageable with corresponding teeth on the other.
 7. Apparatus as setforth in claim 1 in which said mandrel is axially movable relative tosaid supporting packer body, stop means being carried by said mandreland engageable with said supporting packer body to limit said axialmovement in one direction.
 8. Apparatus as set forth in claim 7 in whichsaid mandrel is initially attached to said well packer, said attachmentbeing releasable to permit downward axial displacement of said mandrelfrom said initial position to a position in which said stop meansengages said well packer.
 9. Apparatus as set forth in claim 7 in whichsaid pack-off means is responsive to pressure in said first annularpassage for further axial movement in the same direction relative tosaid supporting packer body while said mandrel remains stationary. 10.In combination a gravel packer and running tool comprising: a. a tubularbody having a perforate liner attached thereto; b. resilient seal meanscarried by said body; c. anchor means carried by said body operable toanchor said seal means to a surrounding well conduit and to acuate saidseal means for sealing between said body and said surrounding conduit;d. an inner well conduit concentrically disposed in said surroundingwell conduit; e. a tubular mandrel attached to said inner well conduitand disposed within said body to provide first and second axiallyextended flow passages for conducting fluids between upper and lowerpoints above and below said seal meanS; f. cross-over flow passage meansextending from said first flow passage and opening externally of saidtubular body at a point below said seal means to provide fluidcommunication between said first and second flow passages through saidperforate liner; and g. pack-off means carried by said tubular mandrelfor limited axial movement thereon and movable from a first positionpermitting fluid flow through said second flow passage to a secondposition sealingly preventing flow through said second flow passage. 11.The combination of claim 10 in which said second flow passage comprisesan annular space surrounding said tubular mandrel within said tubularbody, said pack-off means including a first seal member for engagementwith the outer confines of said annular space, a second seal memberbeing disposed between said packoff means and said tubular mandrelproviding a sliding sealing fit therebetween.
 12. The combination ofclaim 11 in which said pack-off means comprises holddown meanspreventing premature axial displacement of said pack-off means relativeto said tubular mandrel.
 13. The combination of claim 12 in which saidpack-off means is axially displaceable with said mandrel to sealinglyengage and block said second flow passage.
 14. The combination of claim13 in which said holddown means comprises retainer means responsive topressure applied to one end of said packoff means to release saidpack-off means for said limited axial movement on said tubular mandrel.15. The combination of claim 14 in which said hold-down means comprisesfriction means responsive to pressure applied to one end of saidpack-off means to allow said limited axial movement in one directionwhile restricting movement in the opposite direction.
 16. Thecombination of claim 13 comprising stop means carried by said mandreland engageable with a portion of said gravel packer to limit axialmovement of said mandrel in one direction relative to said tubular body.17. The combination of claim 16 in which said stop means is engageablewith said anchor means to apply additional sealing forces to saidresilient seal means.
 18. The combination of claim 10 in which saidsecond flow passage comprises an annular space bounded on the outside bysaid tubular body and on the inside by said tubular mandrel, saidpack-off means comprising a cylindrical sleeve member having a firstseal member for sealingly engaging said tubular body, a second sealmember being disposed between said cylindrical sleeve member and saidtubular mandrel to provide a sliding sealing fit therebetween, saidcylindrical sleeve member being responsive to pressure applied to oneend thereof to effect axial displacement of said cylindrical sleevemember relative to said tubular mandrel.
 19. The combination of claim 18in which said cylindrical sleeve member is initially prevented from saidaxial displacement relative to said tubular mandrel by holddown means,said holddown means being responsive to a predetermined pressure appliedto said one end of said cylindrical sleeve member to release saidcylindrical sleeve member for said limited axial movement whilesealingly engaging said annular space.
 20. The combination of claim 19in which said holddown means comprises friction means responsive topressure applied to the opposite end of said cylindrical sleeve memberto displace said cylindrical sleeve member from said annular space andpreventing re-engagement thereof.